# add the library that runs
add_library(MathFunctions MathFunctions.cxx)

# state that anybody linking to us needs to include the current source dir
# to find MathFunctions.h, while we don't.
target_include_directories(MathFunctions
                           INTERFACE 
                           $<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}>
                           $<INSTALL_INTERFACE:include>
                           )

# should we use our own math functions
option(USE_MYMATH "Use tutorial provided math implementation" ON)
if(USE_MYMATH)

  target_compile_definitions(MathFunctions PRIVATE "USE_MYMATH")

  # first we add the executable that generates the table
  add_executable(MakeTable MakeTable.cxx)
  target_link_libraries(MakeTable PRIVATE tutorial_compiler_flags)

  # add the command to generate the source code
  add_custom_command(
    OUTPUT ${CMAKE_CURRENT_BINARY_DIR}/Table.h
    COMMAND MakeTable ${CMAKE_CURRENT_BINARY_DIR}/Table.h
    DEPENDS MakeTable
    )

  # library that just does sqrt
  add_library(SqrtLibrary STATIC
              mysqrt.cxx
              ${CMAKE_CURRENT_BINARY_DIR}/Table.h
              )

  # state that we depend on our binary dir to find Table.h
  target_include_directories(SqrtLibrary PRIVATE
                             ${CMAKE_CURRENT_BINARY_DIR}
                             )

  # state that SqrtLibrary need PIC when the default is shared libraries
  set_target_properties(SqrtLibrary PROPERTIES
                        POSITION_INDEPENDENT_CODE ${BUILD_SHARED_LIBS}
                        )

  target_link_libraries(SqrtLibrary PUBLIC tutorial_compiler_flags)
  target_link_libraries(MathFunctions PRIVATE SqrtLibrary)
endif()

target_link_libraries(MathFunctions PUBLIC tutorial_compiler_flags)

# define the symbol stating we are using the declspec(dllexport) when
#building on windows
target_compile_definitions(MathFunctions PRIVATE "EXPORTING_MYMATH")

# install rules
# 只有运行make install才会安装在<prefix>/lib or <prefix>/include
# <prefix>的值默认为/usr/local，如果设置CMAKE_INSTALL_PREFIX的值，
# 则安装在${CMAKE_INSTALL_PREFIX}/lib or ${CMAKE_INSTALL_PREFIX}/include目录下
# install(TARGETS MathFunctions DESTINATION lib)
# install(FILES MathFunctions.h DESTINATION include)


# library that just does sqrt
add_library(myString STATIC
  my_string.cxx
)

# state that we depend on our binary dir to find Table.h
target_include_directories(myString PRIVATE
               ${CMAKE_CURRENT_BINARY_DIR}
               )

set(installable_libs MathFunctions tutorial_compiler_flags)
if (TARGET SqrtLibrary)
  list(APPEND installable_libs SqrtLibrary)
endif()

export(TARGETS ${installable_libs} myString
  NAMESPACE MathFunctions::
  FILE MathFunctionsTargets.cmake
)

set(CMAKE_EXPORT_PACKAGE_REGISTRY ON)
export (PACKAGE MathFunctions)
